pain

1 files changed, 547 insertions, 0 deletions

diff --git a/frontend-old/node_modules/@grpc/grpc-js/src/subchannel-call.ts b/frontend-old/node_modules/@grpc/grpc-js/src/subchannel-call.ts
new file mode 100644
index 0000000..b9f3191
--- /dev/null
+++ b/frontend-old/node_modules/@grpc/grpc-js/src/subchannel-call.ts
@@ -0,0 +1,547 @@
+/*
+ * Copyright 2019 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+import * as http2 from 'http2';
+import * as os from 'os';
+
+import { DEFAULT_MAX_RECEIVE_MESSAGE_LENGTH, Status } from './constants';
+import { Metadata } from './metadata';
+import { StreamDecoder } from './stream-decoder';
+import * as logging from './logging';
+import { LogVerbosity } from './constants';
+import {
+  InterceptingListener,
+  MessageContext,
+  StatusObject,
+  WriteCallback,
+} from './call-interface';
+import { CallEventTracker, Transport } from './transport';
+
+const TRACER_NAME = 'subchannel_call';
+
+/**
+ * https://nodejs.org/api/errors.html#errors_class_systemerror
+ */
+interface SystemError extends Error {
+  address?: string;
+  code: string;
+  dest?: string;
+  errno: number;
+  info?: object;
+  message: string;
+  path?: string;
+  port?: number;
+  syscall: string;
+}
+
+/**
+ * Should do approximately the same thing as util.getSystemErrorName but the
+ * TypeScript types don't have that function for some reason so I just made my
+ * own.
+ * @param errno
+ */
+function getSystemErrorName(errno: number): string {
+  for (const [name, num] of Object.entries(os.constants.errno)) {
+    if (num === errno) {
+      return name;
+    }
+  }
+  return 'Unknown system error ' + errno;
+}
+
+export interface SubchannelCall {
+  cancelWithStatus(status: Status, details: string): void;
+  getPeer(): string;
+  sendMessageWithContext(context: MessageContext, message: Buffer): void;
+  startRead(): void;
+  halfClose(): void;
+  getCallNumber(): number;
+}
+
+export interface StatusObjectWithRstCode extends StatusObject {
+  rstCode?: number;
+}
+
+export interface SubchannelCallInterceptingListener
+  extends InterceptingListener {
+  onReceiveStatus(status: StatusObjectWithRstCode): void;
+}
+
+export class Http2SubchannelCall implements SubchannelCall {
+  private decoder: StreamDecoder;
+
+  private isReadFilterPending = false;
+  private isPushPending = false;
+  private canPush = false;
+  /**
+   * Indicates that an 'end' event has come from the http2 stream, so there
+   * will be no more data events.
+   */
+  private readsClosed = false;
+
+  private statusOutput = false;
+
+  private unpushedReadMessages: Buffer[] = [];
+
+  // Status code mapped from :status. To be used if grpc-status is not received
+  private mappedStatusCode: Status = Status.UNKNOWN;
+
+  // This is populated (non-null) if and only if the call has ended
+  private finalStatus: StatusObject | null = null;
+
+  private internalError: SystemError | null = null;
+
+  constructor(
+    private readonly http2Stream: http2.ClientHttp2Stream,
+    private readonly callEventTracker: CallEventTracker,
+    private readonly listener: SubchannelCallInterceptingListener,
+    private readonly transport: Transport,
+    private readonly callId: number
+  ) {
+    const maxReceiveMessageLength = transport.getOptions()['grpc.max_receive_message_length'] ?? DEFAULT_MAX_RECEIVE_MESSAGE_LENGTH;
+    this.decoder = new StreamDecoder(maxReceiveMessageLength);
+    http2Stream.on('response', (headers, flags) => {
+      let headersString = '';
+      for (const header of Object.keys(headers)) {
+        headersString += '\t\t' + header + ': ' + headers[header] + '\n';
+      }
+      this.trace('Received server headers:\n' + headersString);
+      switch (headers[':status']) {
+        // TODO(murgatroid99): handle 100 and 101
+        case 400:
+          this.mappedStatusCode = Status.INTERNAL;
+          break;
+        case 401:
+          this.mappedStatusCode = Status.UNAUTHENTICATED;
+          break;
+        case 403:
+          this.mappedStatusCode = Status.PERMISSION_DENIED;
+          break;
+        case 404:
+          this.mappedStatusCode = Status.UNIMPLEMENTED;
+          break;
+        case 429:
+        case 502:
+        case 503:
+        case 504:
+          this.mappedStatusCode = Status.UNAVAILABLE;
+          break;
+        default:
+          this.mappedStatusCode = Status.UNKNOWN;
+      }
+
+      if (flags & http2.constants.NGHTTP2_FLAG_END_STREAM) {
+        this.handleTrailers(headers);
+      } else {
+        let metadata: Metadata;
+        try {
+          metadata = Metadata.fromHttp2Headers(headers);
+        } catch (error) {
+          this.endCall({
+            code: Status.UNKNOWN,
+            details: (error as Error).message,
+            metadata: new Metadata(),
+          });
+          return;
+        }
+        this.listener.onReceiveMetadata(metadata);
+      }
+    });
+    http2Stream.on('trailers', (headers: http2.IncomingHttpHeaders) => {
+      this.handleTrailers(headers);
+    });
+    http2Stream.on('data', (data: Buffer) => {
+      /* If the status has already been output, allow the http2 stream to
+       * drain without processing the data. */
+      if (this.statusOutput) {
+        return;
+      }
+      this.trace('receive HTTP/2 data frame of length ' + data.length);
+      let messages: Buffer[];
+      try {
+        messages = this.decoder.write(data);
+      } catch (e) {
+        this.cancelWithStatus(Status.RESOURCE_EXHAUSTED, (e as Error).message);
+        return;
+      }
+
+      for (const message of messages) {
+        this.trace('parsed message of length ' + message.length);
+        this.callEventTracker!.addMessageReceived();
+        this.tryPush(message);
+      }
+    });
+    http2Stream.on('end', () => {
+      this.readsClosed = true;
+      this.maybeOutputStatus();
+    });
+    http2Stream.on('close', () => {
+      /* Use process.next tick to ensure that this code happens after any
+       * "error" event that may be emitted at about the same time, so that
+       * we can bubble up the error message from that event. */
+      process.nextTick(() => {
+        this.trace('HTTP/2 stream closed with code ' + http2Stream.rstCode);
+        /* If we have a final status with an OK status code, that means that
+         * we have received all of the messages and we have processed the
+         * trailers and the call completed successfully, so it doesn't matter
+         * how the stream ends after that */
+        if (this.finalStatus?.code === Status.OK) {
+          return;
+        }
+        let code: Status;
+        let details = '';
+        switch (http2Stream.rstCode) {
+          case http2.constants.NGHTTP2_NO_ERROR:
+            /* If we get a NO_ERROR code and we already have a status, the
+             * stream completed properly and we just haven't fully processed
+             * it yet */
+            if (this.finalStatus !== null) {
+              return;
+            }
+            code = Status.INTERNAL;
+            details = `Received RST_STREAM with code ${http2Stream.rstCode}`;
+            break;
+          case http2.constants.NGHTTP2_REFUSED_STREAM:
+            code = Status.UNAVAILABLE;
+            details = 'Stream refused by server';
+            break;
+          case http2.constants.NGHTTP2_CANCEL:
+            code = Status.CANCELLED;
+            details = 'Call cancelled';
+            break;
+          case http2.constants.NGHTTP2_ENHANCE_YOUR_CALM:
+            code = Status.RESOURCE_EXHAUSTED;
+            details = 'Bandwidth exhausted or memory limit exceeded';
+            break;
+          case http2.constants.NGHTTP2_INADEQUATE_SECURITY:
+            code = Status.PERMISSION_DENIED;
+            details = 'Protocol not secure enough';
+            break;
+          case http2.constants.NGHTTP2_INTERNAL_ERROR:
+            code = Status.INTERNAL;
+            if (this.internalError === null) {
+              /* This error code was previously handled in the default case, and
+               * there are several instances of it online, so I wanted to
+               * preserve the original error message so that people find existing
+               * information in searches, but also include the more recognizable
+               * "Internal server error" message. */
+              details = `Received RST_STREAM with code ${http2Stream.rstCode} (Internal server error)`;
+            } else {
+              if (
+                this.internalError.code === 'ECONNRESET' ||
+                this.internalError.code === 'ETIMEDOUT'
+              ) {
+                code = Status.UNAVAILABLE;
+                details = this.internalError.message;
+              } else {
+                /* The "Received RST_STREAM with code ..." error is preserved
+                 * here for continuity with errors reported online, but the
+                 * error message at the end will probably be more relevant in
+                 * most cases. */
+                details = `Received RST_STREAM with code ${http2Stream.rstCode} triggered by internal client error: ${this.internalError.message}`;
+              }
+            }
+            break;
+          default:
+            code = Status.INTERNAL;
+            details = `Received RST_STREAM with code ${http2Stream.rstCode}`;
+        }
+        // This is a no-op if trailers were received at all.
+        // This is OK, because status codes emitted here correspond to more
+        // catastrophic issues that prevent us from receiving trailers in the
+        // first place.
+        this.endCall({
+          code,
+          details,
+          metadata: new Metadata(),
+          rstCode: http2Stream.rstCode,
+        });
+      });
+    });
+    http2Stream.on('error', (err: SystemError) => {
+      /* We need an error handler here to stop "Uncaught Error" exceptions
+       * from bubbling up. However, errors here should all correspond to
+       * "close" events, where we will handle the error more granularly */
+      /* Specifically looking for stream errors that were *not* constructed
+       * from a RST_STREAM response here:
+       * https://github.com/nodejs/node/blob/8b8620d580314050175983402dfddf2674e8e22a/lib/internal/http2/core.js#L2267
+       */
+      if (err.code !== 'ERR_HTTP2_STREAM_ERROR') {
+        this.trace(
+          'Node error event: message=' +
+            err.message +
+            ' code=' +
+            err.code +
+            ' errno=' +
+            getSystemErrorName(err.errno) +
+            ' syscall=' +
+            err.syscall
+        );
+        this.internalError = err;
+      }
+      this.callEventTracker.onStreamEnd(false);
+    });
+  }
+
+  public onDisconnect() {
+    this.endCall({
+      code: Status.UNAVAILABLE,
+      details: 'Connection dropped',
+      metadata: new Metadata(),
+    });
+  }
+
+  private outputStatus() {
+    /* Precondition: this.finalStatus !== null */
+    if (!this.statusOutput) {
+      this.statusOutput = true;
+      this.trace(
+        'ended with status: code=' +
+          this.finalStatus!.code +
+          ' details="' +
+          this.finalStatus!.details +
+          '"'
+      );
+      this.callEventTracker.onCallEnd(this.finalStatus!);
+      /* We delay the actual action of bubbling up the status to insulate the
+       * cleanup code in this class from any errors that may be thrown in the
+       * upper layers as a result of bubbling up the status. In particular,
+       * if the status is not OK, the "error" event may be emitted
+       * synchronously at the top level, which will result in a thrown error if
+       * the user does not handle that event. */
+      process.nextTick(() => {
+        this.listener.onReceiveStatus(this.finalStatus!);
+      });
+      /* Leave the http2 stream in flowing state to drain incoming messages, to
+       * ensure that the stream closure completes. The call stream already does
+       * not push more messages after the status is output, so the messages go
+       * nowhere either way. */
+      this.http2Stream.resume();
+    }
+  }
+
+  private trace(text: string): void {
+    logging.trace(
+      LogVerbosity.DEBUG,
+      TRACER_NAME,
+      '[' + this.callId + '] ' + text
+    );
+  }
+
+  /**
+   * On first call, emits a 'status' event with the given StatusObject.
+   * Subsequent calls are no-ops.
+   * @param status The status of the call.
+   */
+  private endCall(status: StatusObjectWithRstCode): void {
+    /* If the status is OK and a new status comes in (e.g. from a
+     * deserialization failure), that new status takes priority */
+    if (this.finalStatus === null || this.finalStatus.code === Status.OK) {
+      this.finalStatus = status;
+      this.maybeOutputStatus();
+    }
+    this.destroyHttp2Stream();
+  }
+
+  private maybeOutputStatus() {
+    if (this.finalStatus !== null) {
+      /* The combination check of readsClosed and that the two message buffer
+       * arrays are empty checks that there all incoming data has been fully
+       * processed */
+      if (
+        this.finalStatus.code !== Status.OK ||
+        (this.readsClosed &&
+          this.unpushedReadMessages.length === 0 &&
+          !this.isReadFilterPending &&
+          !this.isPushPending)
+      ) {
+        this.outputStatus();
+      }
+    }
+  }
+
+  private push(message: Buffer): void {
+    this.trace(
+      'pushing to reader message of length ' +
+        (message instanceof Buffer ? message.length : null)
+    );
+    this.canPush = false;
+    this.isPushPending = true;
+    process.nextTick(() => {
+      this.isPushPending = false;
+      /* If we have already output the status any later messages should be
+       * ignored, and can cause out-of-order operation errors higher up in the
+       * stack. Checking as late as possible here to avoid any race conditions.
+       */
+      if (this.statusOutput) {
+        return;
+      }
+      this.listener.onReceiveMessage(message);
+      this.maybeOutputStatus();
+    });
+  }
+
+  private tryPush(messageBytes: Buffer): void {
+    if (this.canPush) {
+      this.http2Stream!.pause();
+      this.push(messageBytes);
+    } else {
+      this.trace(
+        'unpushedReadMessages.push message of length ' + messageBytes.length
+      );
+      this.unpushedReadMessages.push(messageBytes);
+    }
+  }
+
+  private handleTrailers(headers: http2.IncomingHttpHeaders) {
+    this.callEventTracker.onStreamEnd(true);
+    let headersString = '';
+    for (const header of Object.keys(headers)) {
+      headersString += '\t\t' + header + ': ' + headers[header] + '\n';
+    }
+    this.trace('Received server trailers:\n' + headersString);
+    let metadata: Metadata;
+    try {
+      metadata = Metadata.fromHttp2Headers(headers);
+    } catch (e) {
+      metadata = new Metadata();
+    }
+    const metadataMap = metadata.getMap();
+    let code: Status = this.mappedStatusCode;
+    if (
+      code === Status.UNKNOWN &&
+      typeof metadataMap['grpc-status'] === 'string'
+    ) {
+      const receivedStatus = Number(metadataMap['grpc-status']);
+      if (receivedStatus in Status) {
+        code = receivedStatus;
+        this.trace('received status code ' + receivedStatus + ' from server');
+      }
+      metadata.remove('grpc-status');
+    }
+    let details = '';
+    if (typeof metadataMap['grpc-message'] === 'string') {
+      try {
+        details = decodeURI(metadataMap['grpc-message']);
+      } catch (e) {
+        details = metadataMap['grpc-message'];
+      }
+      metadata.remove('grpc-message');
+      this.trace(
+        'received status details string "' + details + '" from server'
+      );
+    }
+    const status: StatusObject = { code, details, metadata };
+    // This is a no-op if the call was already ended when handling headers.
+    this.endCall(status);
+  }
+
+  private destroyHttp2Stream() {
+    // The http2 stream could already have been destroyed if cancelWithStatus
+    // is called in response to an internal http2 error.
+    if (!this.http2Stream.destroyed) {
+      /* If the call has ended with an OK status, communicate that when closing
+       * the stream, partly to avoid a situation in which we detect an error
+       * RST_STREAM as a result after we have the status */
+      let code: number;
+      if (this.finalStatus?.code === Status.OK) {
+        code = http2.constants.NGHTTP2_NO_ERROR;
+      } else {
+        code = http2.constants.NGHTTP2_CANCEL;
+      }
+      this.trace('close http2 stream with code ' + code);
+      this.http2Stream.close(code);
+    }
+  }
+
+  cancelWithStatus(status: Status, details: string): void {
+    this.trace(
+      'cancelWithStatus code: ' + status + ' details: "' + details + '"'
+    );
+    this.endCall({ code: status, details, metadata: new Metadata() });
+  }
+
+  getStatus(): StatusObject | null {
+    return this.finalStatus;
+  }
+
+  getPeer(): string {
+    return this.transport.getPeerName();
+  }
+
+  getCallNumber(): number {
+    return this.callId;
+  }
+
+  startRead() {
+    /* If the stream has ended with an error, we should not emit any more
+     * messages and we should communicate that the stream has ended */
+    if (this.finalStatus !== null && this.finalStatus.code !== Status.OK) {
+      this.readsClosed = true;
+      this.maybeOutputStatus();
+      return;
+    }
+    this.canPush = true;
+    if (this.unpushedReadMessages.length > 0) {
+      const nextMessage: Buffer = this.unpushedReadMessages.shift()!;
+      this.push(nextMessage);
+      return;
+    }
+    /* Only resume reading from the http2Stream if we don't have any pending
+     * messages to emit */
+    this.http2Stream.resume();
+  }
+
+  sendMessageWithContext(context: MessageContext, message: Buffer) {
+    this.trace('write() called with message of length ' + message.length);
+    const cb: WriteCallback = (error?: Error | null) => {
+      /* nextTick here ensures that no stream action can be taken in the call
+       * stack of the write callback, in order to hopefully work around
+       * https://github.com/nodejs/node/issues/49147 */
+      process.nextTick(() => {
+        let code: Status = Status.UNAVAILABLE;
+        if (
+          (error as NodeJS.ErrnoException)?.code ===
+          'ERR_STREAM_WRITE_AFTER_END'
+        ) {
+          code = Status.INTERNAL;
+        }
+        if (error) {
+          this.cancelWithStatus(code, `Write error: ${error.message}`);
+        }
+        context.callback?.();
+      });
+    };
+    this.trace('sending data chunk of length ' + message.length);
+    this.callEventTracker.addMessageSent();
+    try {
+      this.http2Stream!.write(message, cb);
+    } catch (error) {
+      this.endCall({
+        code: Status.UNAVAILABLE,
+        details: `Write failed with error ${(error as Error).message}`,
+        metadata: new Metadata(),
+      });
+    }
+  }
+
+  halfClose() {
+    this.trace('end() called');
+    this.trace('calling end() on HTTP/2 stream');
+    this.http2Stream.end();
+  }
+}